Alk(en)yl polyglycoside ether carboxylates are known surfactants. Alk(en)yl polyglycoside ether carboxylate refers to alkyl polyglycoside ether carboxylate and/or alkenyl polyglycoside ether carboxylate. Alk(en)yl polyglycoside ether carboxylates can be obtained by derivatizing alk(en)yl polyglycoside (alk(en)yl polyglycoside refers to alkyl polyglycoside and/or alkenyl polyglycoside) at one or more OH groups of the polyglycoside component of the alk(en)yl polyglycoside by reaction of each of these one or more OH groups with one molecule of ω-halocarboxylic acid or a salt or ester thereof to form an ether and conversion of the carboxylic acid group of the ω-halocarboxylic acid into a carboxylate group.
The alk(en)yl polyglycoside from which the alk(en)yl polyglycoside ether carboxylates can be obtained in the described manner is known as the “alk(en)yl polyglycoside on which the alk(en)yl polyglycoside ether carboxylate is based”. The substituents of the alk(en)yl polyglycoside ether carboxylate which are derived from ω-halocarboxylic acid are called “ether carboxyl groups”.
The number of ether carboxyl groups bearing one molecule of alk(en)yl polyglycoside ether carboxylate in a certain sample of alk(en)yl polyglycoside ether carboxylate is different and is determined by the production process. In a certain sample of alk(en)yl polyglycoside ether carboxylate containing a certain statistical average of ether carboxyl groups pre molecule of alk(en)yl polyglycoside ether carboxylate, the number of ether carboxyl groups per molecule of alk(en)yl polyglycoside ether carboxylate varies from molecule to molecule.
Alk(en)yl polyglycoside ether carboxylates are normally riot pure substances because different fatty alcohol residues, different chain lengths of the polyglycoside units and different degrees of substitution with ether carboxylate groups are usually present in one and the same sample. Where reference is made to alk(en)yl polyglycoside ether carboxylate in the singular, this does not mean that the substance is pure.
Alk(en)yl polyglycosides can be represented by formula (I) below:R1O-[G]p  (I)in which R1 is an alkyl group or an alkenyl group preferably containing 4 to 22 carbon atoms, G is a sugar unit preferably containing 5 or 6 carbon atoms and p is preferably a number of 1 to 10. Alk(en)yl polyglycosides can be produced by standard methods. The production of alk(en)yl polyglycosides is described, for example, in the article by Biermann et al. in Starch/Stärke 45, 281 (1993), in the article by B. Salka in Cosm. Toil. 108, 89 (1993) and in the article by J. Kahre et al. in SÖFW-Journal, No. 8, 598 (1995).
In the production of alk(en)yl polyglycosides, the fatty alcohol is generally used in excess and, after the reaction, is completely removed from the product by distillation or its content in the product mixture is reduced by distillation.
After the reaction, but before distillation, the “crude alk(en)yl polyglycoside” normally contains ca. 50 to 80% of fatty alcohol.
Alk(en)yl polyglycoside ether carboxylate can be produced by reaction of alk(en)yl polyglycoside with ω-halocarboxylic acids in an alkaline medium. Since alk(en)yl polyglycosides have very high viscosities in the molten state, suitable solvents are normally added during the reaction. Organic aprotic solvents are generally used, so that hydrolysis of the halocarboxylic acids or salts or esters thereof is avoided. WO 97/42299 describes the reaction with toluene as solvent.
WO 02/090369 discloses a process for the production of alk(en)yl polyglycoside ether carboxylate by reaction of alk(en)yl polyglycoside with an ω-halocarboxylic acid, a salt or ester thereof in aqueous solution. WO 03/043725 discloses mixtures of alk(en)yl polyglycoside and fatty alcohols and their use. Mixtures of alk(en)yl polyglycoside ether carboxylate and fatty alcohols are unknown in the prior art.